Switching system channel selection



y 1965 J. c. ENGEMAN ETAL 3,185,773

SWITCHING SYSTEM CHANNEL SELECTION 20 Sheets-Sheet 2 Filed May 21, 1962 co z 28 x23 xzzE Fm 0 ma a m EOE 86:26 x22;

. use m J C ENGEMAN INVENTORS L. FR/NG, JR

By 6. J HARTMANN N at ATTORNEY May 25, 1965 .1. c. ENGEMAN ETAL. 3,185,773

SWITCHING SYSTEM CHANNEL SELECTION 20 Sheets-Sheet 5 Filed May 21, 1962 19:26 10.622 u Md; 0? m2: a mz D..w m u J. c. E/VGEMAN wvmrms 1.. FRI/VG. .m.

a. .1. HAnTMA/m ATTORNEY May 25, 1965 J. c. ENGEMAN ETAL 3,185,773

SWITCHING SYSTEM CHANNEL SELECTION Filed May 21, 1962 20 Sheets-Sheet 7 TRUNK LINK J. SW. 9

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47 Tom/5k J. c. ENGEMAN ETAL 3,185,773

SWITCHING SYSTEM CHANNEL SELECTION 20 Sheets-Sheet 12 ATTORNEY May 25, 1965 Filed May 21, 1962 May 25, 1965 J. c. ENGEM-AN ETAL 3,185,773

SWITCHING SYSTEM CHANNEL SELECTION Filed'May 21, 1962 2o Sheets-Sheet 1's TRUNK LINK FRAME 00 TRUNKSWITCH J. C- ENGEMAN Q INVENTORS L. FRI/mm.

a. .1. HARTMANN 9 .av P 1L Mani u 4T TOAWEVI 

1. IN A SWITCHING OFFICE WHEREIN PAIRS OF MUTUALLY DISCONNECTED TERMINALS AT SAID OFFICE MAY BE INTERCONNECTED ONLY OVER A CHANNEL SERIALLY CONNECTED THEREBETWEEN, A PLURALITY OF CHANNELS DIVIDED INTO SUBGROUPS WHERE A PAIR OF TERMINALS TO BE CONNECTED AT SAID OFFICE IS NORMALLY INTECONNECTABLE ONLY OVER A CHANNEL OF A CORRESPONDING SUBGROUP, TESTING MEANS SELECTIVELY CONNECTABLE TO ANY SAID SUBGROUP FOR ASCERTAINING CHANNEL AVAILABILITY IN A SUBGROUP CONNECTED THERETO, MEANS FOR DESIGNATING ANY SAID PAIR OF TERMINALS FOR INTERCONNECTION WITH EACH OTHER OVER A CHANNEL AND FOR CAUSING SAID TESTING MEANS TO BE CONNECTED TO A FIRST SUBGROUP CORRESPONDING TO SAID ONE DESIGNATED PAIR, AND CIRCUIT MEANS (A) CONTROLLED BY SAID TESTING MEANS INCIDENT TO UNAVAILABILITY OF A CHANNEL IN SAID FIRST SUBGROUP FOR CAUSING SAID TESTING MEANS TO BE CONNECTED TO A SECOND SUBGROUP CORRESPONDING TO A PAIR OF OTHER THAN SAIS ONE DESIGNATED PAIR (B) AND CONTROLLED BY SAID TESTING MEANS INCIDENT TO AVAILABILITY OF A CHANNEL IN SAID SECOND SUBGROUP FOR MAKING SAID SECOND SUBGROUP AVAILABLE TO INTERCONNECT AT SAID OFFICE SAID ONE DESIGNATED PAIR WHILE MAINTAINING SAID ONE DESIGNATED PAIR DISCONNECTED FROM SAID OTHER PAIR. 